Native Arbuscular Mycorrhiza Research Articles

Inoculation of Native Arbuscular Mycorrhizae and Bacillus subtilis Can Improve Growth in Vegetable Crops.

Arbuscular mycorrhizal fungi (AMF) and some rhizobacteria are known as plant growth-promoting microorganism (PGPM) as they play significant roles in improving soil fertility structure, plant nutrition, growth, and health. However, little is known about the PGPM potential of AMF and rhizobacteria native to the Rift Valley and highland regions of Ethiopia. Hence, this study aimed to investigate the PGPM effect of single and co-inoculation of AMF and the Bacillus subtilis ALCR46 strain, on tomato (Lycopersicum esculentum L.), onion (Allium cepa L.), and squash (Cucurbita pepo L.) plants. The experimental setup was a randomized complete block design with three replications of the following treatments: (i) inoculation with a consortium of AMF, (ii) co-inoculation with a consortium of AMF and the Bacillus subtilis, (iii) inoculation with Rhizophagus clarus, (iv) co-inoculation with R. clarus and B. subtilis, (v) inoculation with B. subtilis, (vi) plants without inoculation (negative control), and (vii) plants treated with chemical fertilizer (positive control). Plants were maintained in a greenhouse for 60 days, and after harvest, plant growth parameters, percentage of AMF root colonization, and spore number were analyzed. The result shows that the growth of crops significantly increased by co-inoculation with the consortium of AMF and B. subtilis. AMF spore density and root colonization rate were also increased in co-inoculated plants. Highest root colonization, spore number, and mycorrhizal dependency were observed in A. cepa. Our results suggest that there is a synergistic effect between the AMF and B. subtilis ALCR46, and between AMF inoculants. However, the application of present findings under field conditions is required to be confirmed by further studies.

Native arbuscular mycorrhiza colonization in seedling root of dogfruit (Archidendron pauciflorum) planted as seed-ball in field

Arbuscular mycorrhiza (AM) is a mutualistic symbiosis between soil fungi and plants, including dogfruit (Archidendron pauciflorum). Archidendron pauciflorum is a local plant from Southeast Asia, including Indonesia that is used for food and animal forest feed. Planting A. pauciflorum seedlings on revegetation land with a sharp slope is difficult and dangerous to workers. Therefore, seed-ball planting technique is required for revegetation of post-mining sharp slope areas. This research aimed to study the ability of the native AM fungi to colonize A. pauciflorum seedlings grown as a seed-ball in the field for revegetation purposes. The seed-ball was made using three types of fungal inoculum sources, namely control without AM fungi, natural forest, and stockpile inoculum. All colonization structures, such as entry points, coils, arbuscules, and vesicles, were observed. All seedlings were colonized by AM fungi, with root colonization ranging from 2% to 16%. Stockpile inoculum had a higher AM colonization than the natural forest inoculum. Both sources of native AM fungi tended to improve the growth of the seedling. There were two types of AM spores found in all treatments, Glomus sp. 1 and Glomus sp. 2. Glomus sp. 2 is the dominant species of AM fungi in all treatments.

Effects of Native Arbuscular Mycorrhizae Isolated on Root Biomass and Secondary Metabolites of Salvia miltiorrhiza Bge.

Arbuscular mycorrhiza fungi (AMFs) are a group of soil-dwelling fungi that form symbiotic associations with plants, to mediate the secondary metabolism and production of active ingredients in aromatic and medicinal plants. Currently, there is little research on Salvia miltiorrhiza Bge. inoculation with native AMFs and the concomitant effects on growth and secondary metabolites. In this study, S. miltiorrhiza was treated with eight AMFs, i.e., Glomus formosanum; Gl. tenebrosum; Septoglomus constrictum; Funneliformis geosporum; Rhizophagus manihotis; Ambispora gerdemanii; Acaulospora laevis; Ac. tuberculata, to investigate the influence of AMF inoculation on biomass and secondary production under greenhouse conditions in S. miltiorrhiza roots. The results showed that mycorrhiza formation rates were between 54.83 and 86.10%. Apart from Ac. laevis and Gl. tenebrosum treatment, the roots biomass of the other treatment groups was effectively increased, and the fresh and dry weight of the plant inoculated with Fu. geosporum were increased by 86.76 and 86.95%, respectively. Specifically, AMF treatments also impacted on phenolic acids production; inoculation with both Fu. geosporum or Ac. laevis significantly reduced total phenolic acids, whereas the other treatments effectively increased these levels, of which Gl. formosanum generated significant levels. Most AMF-plant symbiotic experiments facilitated phenolic acid accumulation in the secondary metabolites of S. miltiorrhiza (except Ac. laevis). This study showed that most native AMFs inoculation with S. miltiorrhiza promoted roots growth and increased secondary metabolites production (especially phenolic acids). Going forward, inoculation of native AMF is a promising method to improve the quality and yield of S. miltiorrhiza and should be considered during production.

Identification of Dominant Arbuscular Mycorrhizal Fungi in Different Rice Ecosystems

Rice is a staple food in Goa. It is cultivated in three different ecosystems, viz, lowland (khazan), midland (ker) and upland (morod). The present investigation was carried out for two consecutive years, i.e., 2015 and 2016 to study the diversity of arbuscular mycorrhiza (AM) and identify the dominant species in the three different rice ecosystems of Goa. The native dominant AM species identified from the study can be further employed for developing AM inocula. The study revealed 17 AM fungal species recorded from the three ecosystems and belonged to six genera, viz., Acaulospora (9), Rhizoglomus (1), Entrophospora (1), Claroideoglomus (2), Funneliformis (1) and Gigaspora (3). There was dominance of different genera in different ecosystems. The genus Acaulospora was abundant in lowlands, genus Gigaspora in midlands and the genus Claroideoglomus in upland fields. This study suggests the possibility of using inocula of the dominant AM species in the respective ecosystems for increased plant growth and yield.

Effectiveness of native arbuscular mycorrhiza on the growth of four tree forest species from the Santa Marta Mountain, Veracruz (Mexico)

Aim of the study: The aim of this work was to isolate consortia of arbuscular mycorrhizal fungi (AMF) associated to Liquidambar styraciflua in soils of the Santa Marta Mountain in Veracruz, and to select highly effective mycorrhizal consortia on promoting the growth of four tree forest species with economic and ecological importance.Area of study: Santa Marta Mountain, inside the buffer area of the Los Tuxtlas Biological Reserve in Veracruz (México).Materials and methods: Ten composite samples of rhizosphere soil were collected from L. styraciflua trees of 13-15 cm DBH (diameter at breast height). Roots were fixed in FAA solution to determine the mycorrhizal colonization percentage, the abundance of morphospecies, and its effectiveness in promoting the growth of L. styraciflua, Terminalia amazonia, Cordia alliodora, and Cojoba arborea. Soil physical and chemical characteristics were also analysed, and soil type recognition was performed with the Reference Base for Soil FAO-ISRIC World-SICS. Mycorrhizal colonization was determined by the method of clearing and staining roots with trypan blue; total percentage of colonization was estimated by the Linderman-Biermann method. Spores were extracted for counting and identifying morphospecies from each soil sample, those with more effectiveness were selected and inoculated in the four tree species, based upon a completely random design there were evaluated height, number of leaves, total dry weight and foliar area.Main results: Average mycorrhizal colonization percentage was 45% from natural conditions, samples one and four showed 80% of AMF-colonization. Average number of spores was 617 in 100 g-1 of dry soil. Forty-seven AMF-morphospecies were identified. After eight months significant differences were observed in root colonization, height, number of leaves, total dry weight, leaf area and foliar analysis of N5+, P5+ and K+ on plants inoculated with rhizosphere samples of L. styraciflua. Terminalia amazonia and Cojoba arborea showed greater response to the inoculation of AMF, they showed more height, number of leaves and more total dry weight; whereas C. alliodora appears to be low dependent on AMF.Highlights: Diversispora aurantia and Glomus aggregatum are reported by the first time from Mexican humid tropics. Native AMF have potential biotechnological application. The mycorrhizal consortium six (Glomus and Acaulospora) was the more effective in promoting the development of the four tree species used in the experiment.

Improving Phosphorus Nutrition of Upland Rice through Native Arbuscular Mycorrhiza (AM)

Upland rice (Oryza sativa L.) is mostly grown under rainfed, drought prone ecology in aerobic soil condition and is direct seeded. The soils are generally poor in organic matter content, water holding capacity and acidic in nature. A majority of uplands under rice cultivation in India consists of red Alfisols and lateritic soils. These render upland rice poor in acquisition of less mobile nutrients of which phosphorus (P) is most important. This is because, beside formation of poorly soluble complexes of P with iron and aluminum in acidic soil [1], even available P forms remain adsorbed on soil particles making it inaccessible to plant from beyond P depletion zone which is created around effective root absorptive area [2]. This adsorbed P is very slowly diffusible unlike nitrogen and potassium and hence, remained inaccessible unless intercepted by roots. The external mycelia network of arbuscular mycorrhizal fungi (AMF) which is connected to colonized (AMF) plant through roots, serves as extended root surface up to 8 cm beyond root zone [3]. This mycelia network of AMF promotes acquisition of P from outside P depletion zone by intercepting the adsorbed P which is otherwise (under no AM association) not accessible to plant. The soil environment (aerobic condition) of uplands is favorable for AMF activities. Moreover, due to comparatively poor adoption of intensive agriculture in upland ecology, the soil system is less disturbed maintaining the soil microflora diversity, including that of AMF, almost intact [4]. The native AMF flora of upland ecology has been found to be efficient and upland rice is generally responsive to AM [5]. This makes the researchers to think of addressing the constraint of poor P nutrition of upland rice through exploiting native AMF flora. Use of native flora has some added advantages like: (1) these are more adaptive to the target ecology and do not face rejection by the native flora, (2) have less negative ecological consequences in terms of invasive species introduction as unintended contaminants [6].

Impact of Rainfall Pattern on Native Arbuscular-Mycorrhizal Activity Influencing Phosphorus Utilization by Direct Seeded Rainfed Upland Rice (Oryza sativa L.)

Efficacy of native arbuscular mycorrhiza to support phosphorus nutrition of rainfed upland rice was assessed under various rainfall patterns. Native arbuscular-mycorrhiza aided phosphorus acquisition by rainfed upland rice (Oryza sativa L.), over the period of 6 years (in alternate year’s between 1999 and 2009) having variable rainfall pattern, under rice mono-cropping and potential arbuscular-mycorrhiza-supportive rice based rotations were compared. Among these, the 2 years rotation of maize (Zea mays L.) relay cropped by horse gram (Dolichos biflorus L.) in the first year and followed by upland rice in the second year was most mycorrhiza-supportive. While phosphorus uptake in rice was positively correlated (r = 0.6301–0.7821) with the extent of mycorrhizal colonization under various crop rotations, the extent of influence of arbuscular-mycorrhizal colonization was greater in less rainfall year of 2009 (R 2 = 0.5450) than normal rainfall year of 2007 (R 2 = 0.3971). The mycorrhizal advantage to rice under most mycorrhiza supportive crop rotation (maize-horse gram-rice), in terms of mycorrhiza-aided phosphorus acquisition efficiency, on the other hand, was negatively correlated (r = −0.684 to −0.799) with the amount of rainfall received over a period under study (6 years), confirming higher mycorrhizal efficacy under moisture stress. The analysis emphasized the potential of exploiting native arbuscular mycorrhizal fungi as climate resilient agricultural technology component in rainfed ecology under the present climate change scenario leading to reducing moisture availability.

Response of Theobroma cacao and Inga edulis seedlings to cross-inoculated populations of arbuscular mycorrhizal fungi

Response of Theobroma cacao L. (cacao) and the shade tree Inga edulis Mart. (inga) seedlings from an organically-grown cacao plantation to inoculation with native arbuscular mycorrhizae forming fungi (AMF) was studied in a cross-inoculation assay under greenhouse conditions. Seedlings of inga and cacao were grown in pots filled with heat-treated soil from the plantation. Control was heat-treated soil without inoculum and roots of cacao and inga from the plantation were applied as AMF inocula. Undisturbed soil blocks were used as a “positive control” of the inoculation potential of untreated soil and roots combined. No AMF structures were observed in the roots of either species in the heat-treated control. All inocula were infective in both hosts and the differences in the total AMF colonization percentage between the hosts were not significant but inga had significantly higher colonization by hyphal coils and arbuscules. Cacao roots but neither inga roots nor soil block inocula stimulated cacao growth. All inocula significantly increased growth of inga, which had higher relative mycorrhizal responsiveness than cacao. Thus, in spite of the strong infectivity of the inocula in both hosts, cacao and inga responded differently to the same AMF populations. The strong conspecific preference of cacao suggests that attention must be paid to the AMF inoculum used for this species. However, the strong response of inga to cacao root inoculum indicates that the two species may share same AMF symbionts, thus enabling positive interactions between them, including formation of common mycelial networks.

Integration of crop rotation and arbuscular mycorrhiza (AM) inoculum application for enhancing AM activity to improve phosphorus nutrition and yield of upland rice (Oryza sativa L.)

Upland rice (Oryza sativa L.) is a major crop of Eastern India grown during the wet season (June/July to September/October). Aerobic soils of the upland rice system, which are acidic and inherently phosphorus (P) limiting, support native arbuscular mycorrhizal (AM) activity. Attempts were made to improve P nutrition of upland rice by exploiting this natural situation through different crop rotations and application of AM fungal (AMF) inoculum. The effect of a 2-year crop rotation of maize (Zea mays L.) followed by horse gram (Dolichos biflorus L.) in the first year and upland rice in the second year on native AM activity was compared to three existing systems, with and without application of a soil-root-based inoculum. Integration of AM fungal inoculation with the maize-horse gram rotation had synergistic/additive effects in terms of AMF colonization (+22.7 to +42.7%), plant P acquisition (+11.2 to +23.7%), and grain yield of rice variety Vandana (+25.7 to +34.3%).

Determinación de un modelo logístico para evaluación in situ de la colonizacion de micorrizas en pasto dichanthium aristatum (l)

El objetivo fue evaluar la colonización de micorrizas arbusculares nativas, asociadas a raíces de la especie de pasto Dichanthium aristatum (L) en función de factores químicos del suelo, en fincas ganaderas, de la subregión fisiográfica de Sabanas. La determinación del porcentaje de colonización en raíces coloreadas, fue realizada por medio del conteo de micelio, esporas, células auxiliares, vesículas y arbusculos en el microscopio. El modelo o función de probabilidad creada fue utilizado para medir las posibilidades de ocurrencia de la colonización como respuesta a la presencia de ciertos factores químicos del suelo. Para obtener esta función logística se determinó la importancia de cada uno de estos factores de riesgo y sus posibles interacciones. Fueron muestreadas 60 fincas ganaderas. El proceso de modelación logística encontró que los factores que mejor explican el fenómeno de colonización de hongos formadores de micorrizas asociados a rizosfera de pasto angletón fueron el Nitrógeno, Calcio y el Potasio.

Comparative Nitrogen fixation, native arbuscular mycorrhiza formation and biomass production potentials of some grain legume species grown in the iield in the Guinea Savanna Zone of Ghana

An on-station trial was conducted in the experimental field of Savanna Agricultural Research Institute at Nyankpala in the Northern Region of Ghana to assess the nitrogen fixation, native arbuscular mycorrhizal formation and biomass production potentials of cowpea (Vigna unguiculata), devil-bean (Crotalaria retusa), Mucuna pruriens var. utilis(black and white types) and Canavalia ensiformis with maize (Dorke SR) as the reference crop using the total nitrogen difference (TND) method. Plants were fertilized with 40 kg P/ha and 30 kg K/ha at 2 weeks after planting and grown for 55 days after which they were harvested. The harvested biomass (separated into roots, stems and leaves) of eachcrop was oven-dried at 70 oC for 48 h to a constant weight. Cowpea and devil-bean produced approximately 5 and 6 t/ha biomass whereas Mucuna and Canavalia yielded about 2 t/ha biomass each. Although cowpea had the least number of arbuscular mycorrhiza fungal (AMF) spores in its rhizosphere, its roots were the most heavily colonized (34%) and M. pruriens recording below 5% colonization. Apart from C. ensiformis, the test legumes derived over 50% of their total accumulated N from the atmosphere with cowpea being the most efficient (90% Ndfa). Both N and Paccumulations were significantly higher in cowpea than the other legumes due to increased N concentration and dry matter accumulation, respectively. In all the legumes, there was a direct positive correlation between the extent of mycorrhiza formation, biological N fixation and total N uptake. It could, therefore, be concluded that the extensivemycorrhiza formation in cowpea and its high N2-fixing potential resulted in a high shoot N and P uptake leading to a comparatively better growth enhancement. Cowpea could, therefore, be the grain legume for consideration in the selection of a suitable legume pre-crop to cereals for the amelioration of the low fertility of the degraded soils of the Guinea savanna zone of Ghana, and also as a source of food to fill the hunger gap that precedes the growing season in the Northern Region of Ghana.

Effect of Native Bioinoculants on Vegetable Crops Grown on Alkaline Soil Under Field Conditions

ABSTRACT Due to expansive and environment-polluting chemical amendments for reclaiming alkaline salt-affected wastelands that have large share worldwide, it is important to use biological means like native bioinoculants to counteract the alkalinity and increase crop productivity on a sustainable basis. Field experiments were conducted to culture native Arbuscular Mycorrhiza fungi (AMF) on an alkaline soil and to study the efficacy of the native and exotic strains of AMF and Azotobacter in four vegetable crops [Brassica oleracea var. capitata (cabbage), Allium cepa (onion), Solanum melongena (eggplant) and Brassica oleracea var. botrytis (cauliflower)] separately, as well as in combination. The Ricinus communis (castor) was found to be a suitable host for AM culturing on normal soil and Trigonella foenum graecum (fenugreek) on alkaline soil, however, alkalinity affected germination and survival % of R. communis and Zea mays plants significantly. The combined inoculation of native AM fungi and Azotobacter i...

Field microplot performance of the peach-almond hybrid GF-677 after inoculation with arbuscular mycorrhizal fungi in a replant soil infested with root-knot nematodes

The effects of arbuscular mycorrhizae (AM) on the development and nutrition of the peach almond hybrid GF-677 rootstock in a replant soil heavily infested with Meloidogyne javanica were evaluated in field microplot conditions for two growing seasons. There was a significant beneficial effect of mycorrhizal inoculation on plant growth and nutrition in previously pasteurized replant soil. In natural replant soil, early inoculation with a mixed AM inoculum of Glomus intraradices, Glomus mosseae and Glomus etunicatum did not affect growth parameters. Whilst inoculation with these AM fungi led to suppression of root-knot nematode reproduction, natural mycorrhizal colonization of the replant soil with native AM fungi did not.

Cereal/legume rotation effects on cereal growth in Sudano-Sahelian West Africa: soil mineral nitrogen, mycorrhizae and nematodes.

Yield increases of cereals following legumes in rotation have been previously reported for West Africa, but little progress has been made to explain the mechanisms involved. At four sites in Niger and Burkina Faso, field trials with pearl millet (Pennisetum glaucum (L.) R. Br.), cowpea (Vigna unguiculata (L.) Walp), sorghum (Sorghum bicolor (L.) Moench) and groundnut (Arachis hypogaea L.) were conducted from 1996 to 1998 to investigate the role of soil mineral nitrogen (Nmin), native arbuscular mycorrhizae (AM) and nematodes in cereal/legume rotations. Grain and total dry matter yields of cereals at harvest were increased by legume/cereal rotations at all sites. Soil Nmin levels in the topsoil were consistently higher in cereal plots previously sown with legumes (rotation cereals) compared with plots under continuous cereal cultivation. However, these rotation effects on Nmin were much larger with groundnut than with cowpea. Roots of rotation cereals also had higher early AM infection rates compared to continuous cereals. The dominant plant-parasitic nematodes found in all experiment fields were Helicotylenchus sp., Rotylenchus sp. and Pratylenchus sp. In sorghum/groundnut cropping systems, nematode densities were consistently lower in rotation sorghum compared to continuous sorghum. Continuous groundnut had the lowest nematode densities indicating that groundnut was a poor host for the three nematode groups. In millet/cowpea cropping systems with inherently high nematode densities, crop rotations barely affected nematode densities indicating that both crops were good hosts. These results suggest that on the nutrient poor Sudano-Sahelian soils of our study, total dry matter increases of rotation cereals compared with continuous cereals can be explained by higher Nmin and AM infection levels early in the season. The site-specific magnitude of these effects may be related to the efficiency of the legume species to suppress nematode populations and increase plant available N through N2-fixation.

Effects of climatic factors on native arbuscular mycorrhizae and Meloidogyne exigua in a Brazilian rubber tree (Hevea brasiliensis) plantation

The root‐knot nematode Meloidogyne exigua and arbuscular mycorrhizal (AM) fungi may both occur in the roots of Brazilian rubber trees (Hevea brasiliensis). AM fungi may stimulate plant growth whereas nematodes usually reduce it. Variations of native AM fungi and M. exigua populations in soil and roots of rubber trees were studied for one year in a Brazilian plantation. The number of AM spores in the soil was generally greater in the rainy season than in the dry season, although AM colonization of roots was unaffected by season. During the dry season, numbers of juveniles and eggs of M. exigua in roots were lower than in the rainy season. A site without nematodes in the soil or roots showed the greatest numbers of AM spores in soil and highest AM colonization of roots. A negative correlation was observed between the percentage of AM colonization and the number of second‐stage juveniles in soil and second‐stage juveniles and eggs in roots. Microscope observations revealed (i) tissue specificity for each of the microorganisms in the roots, with a cortical location of mycorrhizae and a mainly vascular cylinder location of nematodes, and (ii) that Gigaspora was the most abundant AM genus in the plantation soil.